INVERTEBRATE PALAEONTOLOGY. 557 



Entire Length unknown; length of a specimen consisting of twelve 

 whorls, 0.60 inch ; greatest breadth of same, 0.13 inch ; apical angle a little 

 convex above, divergence about 15°. 



This shell agrees nearly in many respects with the last, especially when 

 we take into consideration the fact that the type-specimen of that form has 

 suffered some accidental compression, which makes its lower volutions appear 

 broader than natural. It should also be mentioned that the specimen from 

 which our figure 12, b, was drawn is likewise a little compressed, so as to 

 make the spire appear somewhat less attenuated above than it would other- 

 wise do. The two forms may belong to one species, but I can hardly think 

 that any amount of distortion by compression could produce the differences 

 seen in the obliquity of the suture, and the length of the lower volutions, 

 represented in our figures 11, b, and 12. b. 



The form here under consideration seems to be more nearly related to a 

 shell described by Matheron, from the Lower Lignite formation of Southern 

 France, than to any other with which I am acquainted.* It, however, has 

 not near so many volutions, which are also a little more convex, while its 

 spire is less attenuated above. Matheron called his species Melania acicula, 

 but there is no probability that it belongs to that genus. As nothing is 

 known in regard to its aperture, however, it may belong to an entirely differ- 

 ent group from our species. 



Locality and position. — Same as last. 



Columua v e r m i c ii I a , v a r . contra ria, M. 



Clausilia contraria, Meek (I860), in Conrad's Smithsonian Check-List N. Am. Eocene Invert. Fossils, 10. 



Along with the foregoing species there were found a few imperfect 

 specimens, apparently, so far as can be determined, agreeing almost exactly 

 with that last described in every respect, excepting that they are dextral. 

 These may represent a distinct species, but I am now inclined to believe 

 that they only belong to a dextral variety of one or the other of the foregoing 

 species — more probably the last. 



* See Matheron's Cat. Me'th. Corps Org. Foss. tlu Depart, de Bouches-du- Rhone, 219, pi. 36, fig. 25. 



